/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Other licenses:
 * -----------------------------------------------------------------------------
 * Commercial licenses for this work are available. These replace the above
 * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
 * database integrations.
 *
 * For more information, please visit: http://www.jooq.org/licenses
 *
 *
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 */
package org.jooq.impl;

import static org.jooq.impl.DSL.nvl2;
import static org.jooq.impl.DSL.one;
import static org.jooq.impl.DSL.zero;
import static org.jooq.impl.Keywords.K_NULLS_FIRST;
import static org.jooq.impl.Keywords.K_NULLS_LAST;

import org.jooq.Clause;
import org.jooq.Context;
import org.jooq.Field;
import org.jooq.SortField;
import org.jooq.SortOrder;

final class SortFieldImpl<T> extends AbstractQueryPart implements SortField<T> {

    /**
     * Generated UID
     */
    private static final long serialVersionUID = 1223739398544155873L;

    private final Field<T>    field;
    private final SortOrder   order;
    private boolean           nullsFirst;
    private boolean           nullsLast;

    SortFieldImpl(Field<T> field, SortOrder order) {
        this.field = field;
        this.order = order;
    }

    @Override
    public final String getName() {
        return field.getName();
    }

    @Override
    public final SortOrder getOrder() {
        return order;
    }

    final Field<T> getField() {
        return field;
    }

    final boolean getNullsFirst() {
        return nullsFirst;
    }

    final boolean getNullsLast() {
        return nullsLast;
    }

    @Override
    public final SortField<T> nullsFirst() {
        nullsFirst = true;
        nullsLast = false;
        return this;
    }

    @Override
    public final SortField<T> nullsLast() {
        nullsFirst = false;
        nullsLast = true;
        return this;
    }

    @Override
    public final void accept(Context<?> ctx) {
        if (nullsFirst || nullsLast) {
            switch (ctx.family()) {

















                // These OSS dialects don't support this syntax at all
                case CUBRID:
                case MARIADB:
                case MYSQL:
                case SQLITE: {
                    Field<Integer> ifNull = nullsFirst ? zero() : one();
                    Field<Integer> ifNotNull = nullsFirst ? one() : zero();

                    ctx.visit(nvl2(field, ifNotNull, ifNull))
                       .sql(", ");

                    acceptFieldAndOrder(ctx);

                    break;
                }

                // DERBY, H2, HSQLDB, ORACLE, POSTGRES
                default: {
                    acceptFieldAndOrder(ctx);

                    if (nullsFirst)
                        ctx.sql(' ').visit(K_NULLS_FIRST);
                    else
                        ctx.sql(' ').visit(K_NULLS_LAST);

                    break;
                }
            }
        }
        else {
            acceptFieldAndOrder(ctx);
        }
    }

    private final void acceptFieldAndOrder(Context<?> ctx) {
        ctx.visit(field);

        if (order != SortOrder.DEFAULT)
           ctx.sql(' ')
              .visit(order.toKeyword());
    }

    @Override
    public final Clause[] clauses(Context<?> ctx) {
        return null;
    }
}
